And even 4x4 isn't necessary, I've taken a 2wd furthur off road than what 99% of 4x4 owners ever do but having 4x4 is like having a fire extinguisher or BOB or PSK, its another piece of gear to have when needed. And modern 4x4's it doesn't give any negatives, the mpg difference between a 4x4 and 2wd truck is maybe .5mpg highway and there isn't really any more maintenance like there was years ago (opponents of 4wd will list mpg and maintenance ans negatives).
The thing that hurt my 2wd truck was not having a low range so when I was offroad it was geared too high.
Though what I said above applies to "part time 4wd systems" there are now many different variations of full time 4wd and AWD that do hurt the milage and cause extra maintenance, for example my v8 powered full size truck gets better gas milage than the v6 AWD tire eating minivan we made the mistake of buying.